Multiple forms of the pituitary polypeptide hormones are commonly observed in pituitary extracts and in plasma. The general aim of the proposed research is to study the biochemical and physiological function of the different molecular forms of adrenocorticotropic hormone (ACTH). A mouse pituitary tumor cell line that synthesizes and secretes multiple forms of ACTH will be used as the source of material for the purification of these different forms of ACTH. The purified peptides will be characterized by size, amino acid composition, and peptide maps. The role of these different forms in the biosynthesis of ACTH will be studied with the pituitary tumor cells and with mouse pituitary cell suspensions. Antisera to the different purified forms of ACTH will be pRepared and radioimmunoassays will be developed. Mouse adrenal cell suspensions and primary cultures of mouse adrenal cells will be used to investigate the effects of both acute and chronic exposure to these different forms of ACTH on steroidogenesis. The control and maintenance of biochemical differences between the anterior and intermediate lobes of the pituitary will be examined using primary cultures of the separated lobes of the mouse pituitary.